Serum ionic fluoride levels in haemodialysis and continuous ambulatory peritoneal dialysis patients

Abstract

High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 ± 3.28 μM/l (range 44-51 μM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 ± 0.350 μM/l. Males in control group showed slightly higher F- levels (1.15 ± 0.334, range 0.55-1.9 μM/l) than females (0.92 ± 0.370, range 0.6-1.5 μM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 ± 1.09, range 0.8-5.2 μM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 ± 1.04, range 1.8-5.2 μM/l) was significantly higher than females (2.38 ± 1.08, range 0.8-5.2 μM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 ± 1.05) than those with age group 13-20 years (1.42 ± 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 ± 1.97 vs 2.5 ± 1.137 μM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 μM/l, posing the risk of renal osteodystrophy. Therefore we recommend frequent monitoring of serum F- concentration in ESRD patients on CAPD/HD, particularly above age 20 years.